Craftsman Riding Lawnmower Won't Start?

Last season the starting of the lawnmower was getting tricky. In order to start, I had to turn the key just a little bit to get it in the right position to start, but it always started.

This year the battery died, so I replaced it, and then I decided to go ahead and do the yearly maintenance on it. So my son changed the spark plug on the right side (now I see there is one on the left too), and changed the oil. When he went to start it, he didn't know to choke it and so he almost drained the battery. I tried it, and it did like it always wanted to, and did respond with just the slightest turn of the key, but the battery wasn't charged enough so it wouldn't start. So then I charged the battery and now when I turn the key nothing happens. No clicking, no nothing. What did I do wrong? Is it the thing that connects to the key?

By judiththompson